(a) Field of the Invention
The present invention relates to a thin film transistor array panel for a liquid crystal display and a method of manufacturing the same.
(b) Description of the Related Art
Liquid crystal display (LCDs) are one of the most widely used flat panel display (FPD) configurations. The liquid crystal display has two panels having electrodes for generating an electric field and a liquid crystal layer interposed between the two panels. The transmittance of incident light is controlled by the intensity of the electric field applied to the liquid crystal layer.
The typical liquid crystal display uses a thin film transistor as a switching element. Data lines and gate lines, which cross each other to define pixels in a matrix array, are formed on the panel on which the thin film transistors are disposed. Further, a pixel electrode is formed in each pixel.
However, in the process of manufacturing the panels for the liquid crystal display, if a conductive material remains on an unintended portion of the panel, in particular between adjacent pixel electrodes or between the pixel electrodes and the data lines, a pixel defect occurs in which the pixels remain in a white state even when the same are controlled to an OFF state. This is a result of shorting of the pixel electrodes with the data lines or adjacent pixel electrodes.
Also, during the operation of the liquid crystal display, after a pixel electrode receives an image signal, which is transmitted via a corresponding data line through the thin film transistor within the same pixel as the pixel electrode, the pixel electrode is then floated before receiving a subsequent image signal. However, the data line continuously transmits image signals to other pixel columns. Accordingly, a voltage of the image signals distorts a potential of the pixel electrode which is in a floating state. This results in an overall reduction in picture quality of the LCD. Such a problem worsens with increases in a coupling capacitance generated between the data lines and the pixel electrodes.
Furthermore, in the LCD panel manufacturing process, because the pixel electrodes and the data lines are formed through different photolithography processes, if there occurs mask misalignment the coupling capacitance between the pixel electrodes and the data lines is varied. In particular, in case of using a stepper as an exposure device to conduct exposure in units of blocks, the degree of misalignment is different between the blocks such that stitches are generated, resulting in a difference of brightness between the blocks. This stitch defect is particularly severe in column or dot inversions drive type LCDs.